NANTUCKET, Massachusetts (CNN) -- Preliminary radar data shows that an EgyptAir 767 jet made a rapid plunge before crashing into the Atlantic Ocean about 60 miles (96 kilometers) off the coast of Nantucket early Sunday morning.

Coast Guard ships and planes are combing the ocean, looking for the remains of Flight 990, which was en route from New York to Cairo with 217 people on board. Of those, as many as 131 may be Americans and at least 62 Egyptians.

EgyptAir Hotlines

EgyptAir has set up the following numbers for families and friends of those on the flight to get information

In the U.S.:
(800) 243-1094

Outside the U.S.:
(202) 245-2244
(202) 244-1460
(202) 418-3690

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New York City Mayor Rudy Giuliani says he'll do everything he can for the families of the people on the plane

While all are feared dead, Coast Guard Rear Adm. Richard Larrabee said his agency "was still conducting a search and rescue mission" at least through the end of the day.

At least one body was recovered, as well as aircraft seats, a wheel, lifejackets and personal effects, including passports, Larrabee said. Two partially-inflated life rafts, which had no signs of burn marks, were found, but he said, "I don't know that you can read anything into that."

The search, by four ships and 11 aircraft, is concentrated on a 36-square-mile patch of ocean surrounding the debris field, Larrabee said. The ocean in the area, which is in international waters, is between 200 and 250 feet (60 to 75 meters) deep, Larrabee said.

The U.S. Navy has agreed to dispatch the USS Grapple to assist in the search. The Grapple, which has special equipment to haul debris from under the ocean, is expected to leave from its home port of Norfolk, Virginia, Sunday evening.

National Transportation Safety Board Chairman Jim Hall said preliminary radar recordings show that the plane, which had reached its cruising altitude of 33,000 feet (9,900 meters), suddenly plunged to 19,100 feet (5,730 meters) in just 36 seconds. He stressed that those radar recordings are preliminary and come from a single radar site.

EgyptAir Flight 990 had originated in Los Angeles on Saturday evening. After stopping at Kennedy International Airport in New York to take on additional passengers, it departed for Cairo at 1:19 a.m. ET Sunday, nearly three hours later than scheduled.

After the plane vanished from radar, the FAA notified the Coast Guard of the disappearance about 2:15 a.m. Search planes and ships were immediately dispatched, and the first debris was spotted at 6:30 a.m. "in the general vicinity of the last known point of contact," Larrabee said.

In Cairo, New York and Los Angeles, airline officials set up private rooms for family members of victims to gather, grieve and receive information and counseling.

"Our main concern now is to do our best to help the families of the victims, here in Egypt and the United States. And we will take all the necessary measures," said EgyptAir's chairman, Mohammed Fahim Rayan, who said he and a team from the airline will fly to the United States on Monday.

On board the aircraft were 199 passengers, 15 crew members and three EgyptAir employees traveling but not on duty, according to the airline. Among the passengers were 62 Egyptians, two Sudanese, three Syrians and one Chilean.

The nationality of the other 131 passengers was not immediately known, Rayan said. But the U.S. State Department reported to the NTSB that the only other country whose nationals were on board the aircraft was the United States.

New York City Mayor Rudy Giuliani, who has seen the passenger list, says "it appears to me that this covers a large, large cross-section of America."

"There are people from California and people from the Midwest and people from Vermont and ... Maryland, so (notifying relatives will be) a very, very complex task," he said.

One passenger on EgyptAir Flight 990 got off the jetliner in New York.

Robert Boyle, executive director of the Port Authority, which operates Kennedy airport, identified the man as Edward McLoughlin, a contract employee for EgyptAir who is vice president for the Family Enterprise Institute.

At midday Sunday, McLoughlin spoke at a news conference called by the Port Authority and said he was contacting families of the passengers on the flight on behalf of EgyptAir.

"He was questioned by Port Authority Police at 8 a.m. and several times since then. His story checks out," Boyle said.

"We work with EgyptAir to try to help the families in terms of the notification process, their support," McLoughlin told reporters.

Under international aviation conventions, it is up to the country where an airplane is registered to investigate crashes in international waters. In this case, that country is Egypt, but Hall said the Egyptian government has requested that the NTSB take the lead in investigating the accident.

"We will devote all the necessary resources to determine what caused this aircraft to crash," Hall said. "We are beginning what may be a long investigation, and we are prepared to do what it takes to find the answers to the questions we are seeking."

Though FBI agents have joined the investigation and the cause of the crash remains very much a mystery, U.S. officials, from President Bill Clinton on down emphasized that there is no evidence of foul play.

"I think it's better if people draw no conclusions," said Clinton, who called Egyptian President Hosni Mubarak to offer condolences.

CNN has learned that on September 24, the Federal Aviation Administration sent a circular to government agencies warning of a bomb threat against flights departing from Los Angeles or New York. But the warning was later rescinded because the threat came from a prison inmate and was not considered credible.

EgyptAir identified the main pilot as Hatem Roushdi, who had more than 10,000 hours of flight experience. Colleagues described him as a "very experienced pilot."

The airline said he had been in contact with his son, also an EgyptAir pilot, just hours before leaving.

Rayan said there were three captains and two co-pilots on the plane, an unusually large number because of the length of the trip.

EgyptAir has suffered four fatal crashes since 1971, the most recent in June 1986. In the worst of those crashes, an EgyptAir 707 crashed into a textile mill during an approach to the Bangkok, Thailand, airport on Christmas Day, 1976, killing 43 passengers, nine crew members and 20 people on the ground.

The Boeing 767 has been used by commercial airlines since 1982 and 700 had been delivered to the airlines as of this past April. EgyptAir put the doomed jetliner into service in 1989.

Prior to Sunday, at least three 767s been involved in serious crashes, including a LAUDA 767 that went down in Thailand in May 1991 after its thrust reversers were accidentally deployed in flight. All 223 aboard were killed in that crash.

The only other with fatalities was an Ethiopian Airline flight that crashed trying to land during a hijacking in November 1996, killing 127 people.